Datacenter Ethernet (DCE) is an architectural collection of Ethernet extensions designed to improve Ethernet networking and management in the data center. Multi-pathing and full bisectional bandwidth are some of the major advantages of DCE. Cisco Fabric Path (FP) and the counterpart Internet Engineering Task Force (IETF) Transparent Interconnect of Lots of Links (TRILL) standard are some of the commonly deployed DCE technologies. A fabric extender (FEX) is a Top of the Rack switch to which datacenter servers are connected. FEXes are simple devices that do not incorporate any switching or routing. They act as remote line cards for their parent switches thereby simplifying datacenter management.
Recent deployments support datacenter technologies all the way to the host server level, thereby making the end hosts DCE capable. To further improve the data center and provide multi-chassis redundancy, emulated switches (e.g., a virtual port channel (VPC)) are supported with FEX devices. Emulated switches correspond to two or more underlying peer link switches, e.g., server hosts, in the layer 2 multipath (LAMP) network, while the FEX devices extend the available number of network ports for a supervisory switch, e.g., a switch at the data center access layer. To provide redundancy, two switches may be employed to alleviate problems associated with failures. These two switches are referred to as “peer” switches. To ensure consistency and redundancy, the peer switches exchange source and destination address information for their respective network communication flows. However, with the use of emulated switches and FEX devices, the number of source and destination addresses to be shared may increase to an unmanageable level, and thus traditional address sharing mechanisms do not scale well. In addition, many of the large number of addresses may not be used, thereby wasting expensive look up table resources.